To Robyn Joan, who did her best to interfere.

Preface

Back in the 1950s, I wrote a series of six derring-do novels about David "Lucky" Starr and his battles against malefactors within the Solar System. Each of the six took place in a different region of the system, and in each case I made use of the astronomical facts - as they were then known.

Now, a quarter-century later, Fawcett is bringing out the novels in new editions; but what a quarter-century it has been! More has been learned about the worlds of our Solar System in this last quarter-century than in all the thousands of years that went before.

LUCKY STARR AND THE BIG SUN OF MERCURY was written in 1955 and at that time, astronomers were convinced that Mercury presented only one face to the Sun, and that it rotated on its axis in 88 days, which was exactly the length of the year. I made that conviction a central part of the plot of the book.

In 1965, however, astronomers studied radar-beam reflections from the surface of Mercury and found, to their surprise, that this was not so. Mercury rotates on its axis in 59 days, so that there is no perpetual day-side or night-side.

Every part of the planet gets both day and night, and the Sun moves in a rather complicated path in Mercury's sky, growing larger and smaller, and backtracking on some occasions. If I were writing this book today, I would take all this into account, I hope my Gentle Readers enjoy this book anyway, as an adventure story, but please don't forget that the advance of science can outdate even the most conscientious science-fiction writer and that my astronomical descriptions are no longer accurate in all respects.

Isaac Asimov